In modern optical communication systems, the bandwidth of channels provided along optical fibers may be relatively large. For example, a single optical channel may have a bandwidth of 100 Gbps or more.
A number of techniques are known for making use of the bandwidth available in optical fibers. In some techniques, a large number of individual channels may be carried within a fiber, each channel operating at a particular wavelength. An example of this is Dense Wavelength Division Multiplexing (DWDM). In some DWDM systems, 80 or more wavelengths may be carried within a fiber. Multi-wavelength sources capable of generating dozens of wavelengths simultaneously, such as quantum dot lasers, may be used to generate the large number of individual channels carried within a fiber.
In a basic communication network, a network of N nodes may be interconnected by N·(N−1) unidirectional links in order to allow direct communication between each of the N nodes. However, given the large bandwidth of modern optical channels, the use of a full set of N·(N−1) unidirectional links to interconnect N nodes may be impractical and/or unnecessary. Various practical networking configurations are known for optical networks in which N nodes may be interconnected by fewer than N·(N−1) links, and where bandwidth is dynamically shared along each provided link. One method of sharing bandwidth of a link is Time Division Multiplexing (TDM). In some TDM systems, the wavelengths carried along a particular fiber link are changed on a per timeslot basis.